Cet article présente les résultats d’une enquête menée en 2021 sur le consentement à l’impôt en France. Nous définissons trois mesures du consentement, que nous mettons en regard avec les ...caractéristiques socioéconomiques et plusieurs critères d’opinion des personnes interrogées. Notre analyse économétrique révèle que la connaissance du système fiscal, la confiance dans les institutions, et la perception d’une bonne utilisation de l’argent public sont positivement et fortement corrélées au consentement à l’impôt. La question de la justice fiscale joue aussi un rôle important: la perception d’une « juste » redistribution et d’une « juste » contribution des différents niveaux de revenus est positivement corrélée au consentement à l’impôt.
This article presents the results of a survey conducted in 2021 to evaluate tax morale in France. Three measures of tax morale are defined and regressed on socio-economic characteristics and several opinion criteria. The econometric analysis shows that knowledge of the tax system, trust in government, and the perception of good use of public money are positively and strongly correlated with tax morale. Perception of fairness of the tax system also plays an important role: the perception of “fair” redistribution and the perception that different income levels “fairly contribute” are positively correlated with tax morale.
Cet article présente les résultats d’une étude sur les territoires dont sont originaires les « Gilets jaunes », au début de la mobilisation. Dès le premier samedi de mobilisation, le 17 novembre ...2018, ce mouvement se démarque par son caractère local et sa couverture nationale. À partir de données inédites de la mobilisation sur Facebook, nous montrons une forte corrélation entre mobilisation online (sur Facebook) et mobilisation offline (blocages des ronds-points). Nous réalisons alors une cartographie fine et contrastée de la contestation. L’étude économétrique met en évidence le rôle de la mobilité pour expliquer les origines du mouvement, au travers notamment du passage des routes à 80 km/h et des distances domicile-travail.Classification JEL : F15, J40, J60, J80, C83.
In Mali's cotton belt, spatial variability in management practices, soil fertility and rainfall strongly impact crop productivity and the livelihoods of smallholder farmers. To identify crop growth ...conditions and hence improve food security, accurate assessment of local crop production is key. However, production estimates in heterogeneous smallholder farming systems often rely on labor-intensive surveys that are not easily scalable, nor exhaustive. Recent advances in high-resolution earth observation (EO) open up new possibilities to work in heterogeneous smallholder systems. This paper develops a method to estimate individual crop production at farm-to-community scales using high-resolution Sentinel-2 time series and ground data in the commune of Koningue, Mali. Our estimation of agricultural production relies on (i) a supervised, pixel-based crop type classification inside an existing cropland mask, (ii) a comparison of yield estimators based on spectral indices and derived leaf area index (LAI), and (iii) a Monte Carlo approach combining the resulting unbiased crop area estimate and the uncertainty on the associated yield estimate. Results show that crop types can be mapped from Sentinel-2 data with 80% overall accuracy (OA), with best performances observed for cotton (Fscore 94%), maize (88%) and millet (83%), while peanut (71%) and sorghum (46%) achieve less. Incorporation of parcel limits extracted from very high-resolution imagery is shown to increase OA to 85%. Obtained through inverse radiative transfer modeling, Sen2-Agri estimates of LAI achieve better prediction of final grain yield than various vegetation indices, reaching R2 of 0.68, 0.62, 0.8 and 0.48 for cotton, maize, millet and sorghum respectively. The uncertainty of Monte Carlo production estimates does not exceed 0.3% of the total production for each crop type.
•Crop production assessed with a maximum model uncertainty of 0.33% at village level•Crop type map from Sentinel-2 achieves 80% OA.•Maximum LAI is the best yield estimator (among various vegetation indices).•Red edge and NIR bands are the more important features for crop type classification.
The performance of Least Squares (LS) estimators is studied in shape-constrained regression models under Gaussian and sub-Gaussian noise. General bounds on the performance of LS estimators over ...closed convex sets are provided. These results have the form of sharp oracle inequalities that account for the model misspecification error. In the presence of misspecification, these bounds imply that the LS estimator estimates the projection of the true parameter at the same rate as in the well-specified case.
In isotonic and unimodal regression, the LS estimator achieves the nonparametric rate n
−2/3 as well as a parametric rate of order k/n up to logarithmic factors, where k is the number of constant pieces of the true parameter. In univariate convex regression, the LS estimator satisfies an adaptive risk bound of order q/n up to logarithmic factors, where q is the number of affine pieces of the true regression function. This adaptive risk bound holds for any collection of design points. While Guntuboyina and Sen Probab. Theory Related Fields 163 (2015) 379–411 established that the nonparametric rate of convex regression is of order n
−4/5 for equispaced design points, we show that the nonparametric rate of convex regression can be as slow as n
−2/3 for some worst-case design points. This phenomenon can be explained as follows: Although convexity brings more structure than unimodality, for some worstcase design points this extra structure is uninformative and the nonparametric rates of unimodal regression and convex regression are both n
−2/3. Higher order cones, such as the cone of β-monotone sequences, are also studied.
The innate immune system is the first line of defense in response to nonself and danger signals from microbial invasion or tissue injury. It is increasingly recognized that each organ uses unique ...sets of cells and molecules that orchestrate regional innate immunity. The cells that execute the task of innate immunity are many and consist of not only "professional" immune cells but also nonimmune cells, such as renal epithelial cells. Despite a high level of sophistication, deregulated innate immunity is common and contributes to a wide range of renal diseases, such as sepsis-induced kidney injury, GN, and allograft dysfunction. This review discusses how the innate immune system recognizes and responds to nonself and danger signals. In particular, the roles of renal epithelial cells that make them an integral part of the innate immune apparatus of the kidney are highlighted.
The Frank-Starling mechanism is a fundamental regulatory property which underlies the cardiac output adaptation to venous filling. Length-dependent activation is generally assumed to be the cellular ...origin of this mechanism. At the heart scale, it is commonly admitted that an increase in preload (ventricular filling) leads to an increased cellular force and an increased volume of ejected blood. This explanation also forms the basis for vascular filling therapy. It is actually difficult to unravel the exact nature of the relationship between length-dependent activation and the Frank-Starling mechanism, as three different scales (cellular, ventricular and cardiovascular) are involved. Mathematical models are powerful tools to overcome these limitations. In this study, we use a multiscale model of the cardiovascular system to untangle the three concepts (length-dependent activation, Frank-Starling, and vascular filling). We first show that length-dependent activation is required to observe both the Frank-Starling mechanism and a positive response to high vascular fillings. Our results reveal a dynamical length dependent activation-driven response to changes in preload, which involves interactions between the cellular, ventricular and cardiovascular levels and thus highlights fundamentally multiscale behaviors. We show however that the cellular force increase is not enough to explain the cardiac response to rapid changes in preload. We also show that the absence of fluid responsiveness is not related to a saturating Frank-Starling effect. As it is challenging to study those multiscale phenomena experimentally, this computational approach contributes to a more comprehensive knowledge of the sophisticated length-dependent properties of cardiac muscle.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
SLOPE MEETS LASSO Bellec, Pierre C.; Lecué, Guillaume; Tsybakov, Alexandre B.
The Annals of statistics,
12/2018, Letnik:
46, Številka:
6B
Journal Article
Recenzirano
Odprti dostop
We show that two polynomial time methods, a Lasso estimator with adaptively chosen tuning parameter and a Slope estimator, adaptively achieve the minimax prediction and ℓ₂ estimation rate (s/n) ...log(p/s) in high-dimensional linear regression on the class of s-sparse vectors in ℝp. This is done under the Restricted Eigenvalue (RE) condition for the Lasso and under a slightly more constraining assumption on the design for the Slope. The main results have the form of sharp oracle inequalities accounting for the model misspecification error. The minimax optimal bounds are also obtained for the ℓq estimation errors with 1 ≤ q ≤ 2 when the model is well specified. The results are nonasymptotic, and hold both in probability and in expectation. The assumptions that we impose on the design are satisfied with high probability for a large class of random matrices with independent and possibly anisotropically distributed rows. We give a comparative analysis of conditions, under which oracle bounds for the Lasso and Slope estimators can be obtained. In particular, we show that several known conditions, such as the RE condition and the sparse eigenvalue condition are equivalent if the ℓ₂-norms of regressors are uniformly bounded.
Inorganic phosphate has numerous biomedical functions. Regulated primarily by the kidneys, phosphate reaches abnormally high blood levels in patients with advanced renal diseases. Since phosphate ...cannot be efficiently removed by dialysis, the resulting hyperphosphatemia leads to increased mortality. Phosphate is also an important component of the environmental chemistry of surface water. Although required to secure our food supply, inorganic phosphate is also linked to eutrophication and the spread of algal blooms with an increasing economic and environmental burden. Key to resolving both of these issues is the development of accurate probes and molecular receptors for inorganic phosphate. Yet, quantifying phosphate in complex aqueous media remains challenging, as is the development of supramolecular receptors that have adequate sensitivity and selectivity for use in either blood or surface waters. Metal-based receptors are particularly well-suited for these applications as they can overcome the high hydration enthalpy of phosphate that limits the effectiveness of many organic receptors in water. Three different strategies are most commonly employed with inorganic receptors for anions: metal extrusion assays, responsive molecular receptors, and indicator displacement assays. In this review, the requirements for molecular receptors and probes for environmental applications are outlined. The different strategies deployed to recognize and sense phosphate with metal ions will be detailed, and their advantages and shortfalls will be delineated with key examples from the literature.
We discuss and review the strategies of metal-based receptors targeting phosphate.
The advent of chemical tools for cellular imaging--from organic dyes to green fluorescent proteins--has revolutionized the fields of molecular biology and biochemistry. Lanthanide-based probes are a ...new player in this area, as the last decade has seen the emergence of the first responsive luminescent lanthanide probes specifically intended for imaging cellular processes. The potential of these probes is still undervalued by the scientific community. Indeed, this class of probes offers several advantages over organic dyes and fluorescent proteins. Their very long luminescence lifetimes enable quantitative spatial determination of the intracellular concentration of an analyte through time-gating measurements. Their emission bands are very narrow and do not overlap, enabling the simultaneous use of multiple lanthanide probes to quantitatively detect several analytes without cross-interference. Herein we describe the principles behind the development of this class of probes. Sensors for a desired analyte can be designed by rationally manipulating the parameters that influence the luminescence of lanthanide complexes. We will discuss sensors based on varying the number of inner-sphere water molecules, the distance separating the antenna from the lanthanide ion, the energies of excited states of the antenna, and PeT switches.
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